1. Field of the Invention
The present invention relates to a door lock, and more particularly to a door lock enabling the user to escape outdoors without using the key to unlock the lock even when the door is locked.
2. Description of Related Art
A door normally has an inner handle and an outer handle to respectively retract the latch bolt so as to open the door. However, when the door is locked from inside at night to prevent any unauthorized personnel to break into the home, the user will have to at least operate the inner handle and the knob to unlock the latch bolt so as to open the door. When there is an emergency inside the house, time is the most important factor for the people to escape outdoors. Therefore, when the door is locked, seconds delay trying to open the door from inside the house might become lethal.
A conventional door usually is equipped with a primary dead bolt and a secondary dead bolt. The primary dead bolt is able to be operated by a knob and the secondary dead bolt can only be operated by a proper key. Therefore, for the sake of safety, some householders often lock the door by activating the secondary dead bolt at night with the key. However, when there is a fire or other emergency requiring the family members to escape outdoors, the time to find the key to deactivate the secondary dead bolt often is the cause of casualty.
To overcome the shortcomings, the present invention tends to provide an improved door lock to mitigate and obviate the aforementioned problems.
The primary objective of the present invention is to provide an improved door lock to enable the user to simultaneously deactivate the primary dead bolt and the secondary dead bolt by operation of the inner handle so as to allow the user to have access to the outside of the house even when the primary dead bolt and the secondary dead bolt are locked.
In order to accomplish the foregoing objective, the door lock of the present invention has a primary dead bolt securely attached to a first linking plate and operably controlled by a knob, a latch adapted to be controlled by an outer handle and a secondary dead bolt operably adapted to be controlled by a key, wherein the primary dead bolt, the latch and the secondary dead bolt are adapted to be operably controlled by an inner handle. Therefore, even when the primary dead bolt and the secondary dead bolt are locked by activating the knob and the key, operation of the inner handle is able to deactivate the locked primary dead bolt and the secondary dead bolt simultaneously as well as the latch.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.